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About this blog

I'm a well-known mainframe performance guy, with almost 30 years of experience helping customers manage systems. I also dabble in lots of other technology. I've sought to widen the Performance role, incorporating aspects of infrastructural architecture.
I'm a world-famous podcaster and screencaster (albeit VERY thinly spread). :-)

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Over the years I’ve written emails with data collection requirements dozens of times, with varying degrees of clarity. It would be better, wouldn’t it, to write it once. I don’t think I can get out of the business of writing such emails entirely but here’s a goodly chunk of it. Another thing that struck me is that the value of some types of data has increased enormously... [More]

You wouldn’t put all your eggs in one basket, CICSwise, would you?
A naive reading of the CICS TS 5.1 announcement materials might lead you to suppose you could .
This post is about thinking about your CICS region portfolio in the light of this announcement. While every CICS release introduces capabilities that makes it worthwhile to review your region portfolio,
5.1 majors on... [More]

As you will’ve seen in
WLM Response Time Distribution Reporting With RMF I’ve been thinking about WLM Response Time goals quite a bit recently.
And this post continues the train of thought. It’s very easy to think of WLM Service Classes as being self contained.
For many that’s true - and only their own performance numbers need to be considered for us to understand their... [More]

When I first heard of Flash Express as part of the zEC12 announcement -
some time before announcement - I thought of one use case above all,
and one of particularly poignant resonance with some of my readers: Dump capture amelioration. Then, in the marketing materials, I heard of others.
And the discussions have grown more numerous recently.
So it’s time I expressed (pardon the pun) my... [More]

There was a time before blogging and what I'm about to talk about is something I used to explain quite often back in those days. Reminded by a current customer situation - and needing to explain it again - I thought it time to do it this way. (Here I'm presenting a simplified view, but one that covers the salient features that might help you.) The CICS / DB2 Connection code provides a number of... [More]

Every year I like to debut one new presentation, though that isn't a firm rule:
In 2012 I debuted
"Send In The Clones" (SITC) 1 and
"I Know What You Did Last Summer" (IKWYDLS), but actually
only the first one was written in 2012. Of course presentations are "slow trains coming": I widely trailed my desire to write
IKWYDLS in 2011 and finally revealed it early this year.
(In fact it... [More]

Round about now you'd be expecting posts to be geared towards the recent zEC12 announcement, or perhaps CICS TS 5.1 or the DB2 11 Preview, or IDAA V3.
So what this post is about will probably have slipped by unnoticed.
After all you don't spend all your time looking for obscure New Function APARs, do you? But I think some of you will find this one of value, or at least quite interesting. (I... [More]

This post is about unusual ways of using the SMF 30 Usage Data information, some of which you're certain to want if you're managing z/OS systems' performance. A long time ago I noticed character strings in SMF 30 records that looked like product names. (As is my wont I was looking at the raw Type 30 records for a different purpose and spotted them.) Some time later I figured out these were Usage... [More]

I can tell when a CICS region came up - without looking at CICS-specific instrumentation. What's more I can repeat the "trick" for any of MQ, DB2, IMS, etc - and so can you . I've just started work on a new piece of reporting. I'll call it "raddrspc" as that's the name of the REXX EXEC that I'm writing. It's about address spaces - most notably long-running ones. In the... [More]

It's said that imitation is the sincerest form of flattery. In this Social Media age I'd say indirection comes a pretty close second. Indeed there's a nice term for it: "link love". Standard advice is not to just post links to the content of others. In reality the word "just" should probably be inserted: Don't just post links to the content of others. In that vein I want to... [More]

The CICS Monitor Trace SMF Record (Type 110) has got to be one of the most complicated SMF records in existence - and for good reason. Which is precisely why I'm not going to attempt to process the raw records in my code. (And why PMCICS doesn't support releases after a certain point.) But the "and for good reason" hints at the fact I think this is a tremendously valuable type of... [More]

If you think this title is obscure bear in mind the original working title was "Send In The Hobgoblins". 1 When I started to write - actually before the "mind mapping" stage - it was going to be all about inconsistency in the way bits of systems are named. You'll see some of that reflected in the finished article (pun intended) but the post has mostly gone in a different... [More]

You'd think it would be pretty simple to draw a line. Right? This post discusses an enhancement I'd like to make to my current reporting - and I'm pretty sure that technically I can do it. The question is whether I should . Consider my current "Memory by address space within Service Class" graph. Here's a sample: And here's what I think I might like it to look like: Obviously the line's... [More]

This is the post I was going to write before the discussion that led to CICS VSAM Buffering arose. It's about getting more insight into how WLM is set up and performing than RMF Workload Activity Report data alone allows. I recognise some of this can be done with the WLM policy in hand. But this is about an SMF-based approach. (The piece you can't do with SMF is discerning the WLM classification... [More]

Four score and seven years ago (or so it seems) the Washington Systems Center published a set of mainframe Data-In-Memory studies. These were conducted by performance teams in various IBM labs and were quite instructive and inspiring. I wish I could find the form number (and a fortiori a PDF version) for this book. Anyone? Even hardcopy would be really nice. The reason I mention this is because... [More]